A waste stream flows at 2,000 liters/day with a concentration of 60 mg/l of hazardous chemical A. The chemical undergoes a first-order decay reaction with k = 0.01/sec. Complete performance analyses of the three common ideal chemical reactors to determine the effluent concentration of chemical A for the following conditions: 1. CSTR, V = 500 liters 2. PFR, V = 14 liters 3. Batch Reactor, V = 500 liters (i.e., 4 batches of waste processed per day to handle the total daily volume of 2,000 liters) with a reaction time τ = 10 min. Compare and contrast the performance of each reactor type.

A waste stream flows at 2,000 liters/day with a concentration of 60 mg/l of hazardous chemical A. The chemical undergoes a first-order decay reaction with k = 0.01/sec. Complete performance analyses of the three common ideal chemical reactors to determine the effluent concentration of chemical A for the following conditions: 1. CSTR, V = 500 liters 2. PFR, V = 14 liters 3. Batch Reactor, V = 500 liters (i.e., 4 batches of waste processed per day to handle the total daily volume of 2,000 liters) with a reaction time τ = 10 min. Compare and contrast the performance of each reactor type.

Sustainable Energy

2nd Edition

ISBN:9781337551663

Author:DUNLAP, Richard A.

Publisher:DUNLAP, Richard A.

Chapter14: Ocean Thermal Energy Conversion And Ocean Salinity Gradient Energy

Section: Chapter Questions

Problem 20P

See similar textbooks

Similar questions

Problem 2 At a Cleanup site, a contaminated ground was dug out and treated in a completely mixed aerated lagoon. The following information is collected using a completely mixed batch reactor in a laboratory. Assuming a first-order reaction. a) Estimate the rate constant, k. b) The time required to achieve 95% reduction in the original concentration. c) Estimate the initial concentration at t=0. Time(days) 5 30 Waste Concentration (mg/L) 500 100
An ideal continuous stirred tank reactor (CSTR) has an influent containing Chemical X at a concentration of 150 mg/l and a flow rate of 100 gpm (380 liters/min). Chemical X undergoes a first-order decay reaction having k = 0.40 hr –1 . Determine: 1a. The required detention time and volume of the CSTR if the effluent concentration contains 20 mg/l of Chemical X. Express the volume in both gallons and liters. 1b. Use a spreadsheet to perform the necessary calculations and then use the spreadsheet's graphing tools to plot two graphs; i. Pollutant removal efficiency, 1e, on the vertical or y-axis versus hydraulic detention time on the horizontal or x-axis. ii. Effluent concentration, CX1 , on the vertical or y-axis versus hydraulic detention time on horizontal or x-axis. Analyze and comment on the significance of the graphs. 1c. How many times larger must a CSTR be than a PFR to achieve 80 percent pollutant removal or conversion? 1d. How many times larger must a CSTR be than a PFR to…
You are considering available options to meet new effluent quality standards for a particular contamination being treated at your plant. Currently you are operating with two reactors connected in parallel as shown in Figure 1(a). One reactor is a plug flow reactor (PFR), the other is a completely stirred tank reactor (CSTR). The following information is available: Design flow, Q: 60 L/min Influent concentration, Co: 10 mg/L Order of reaction: 1st Order Decay constant, k: 0.25 min! Volume of PFR, Vp: 360 L Volume of CSTR, Vc: 2280 L Using the above information, determine: a. The residence time, t, in each reactor; b. The effluent concentration from the PFR; C. The effluent concentration from the CSTR. d. The resulting effluent quality with the two reactors in parallel. You want to investigate whether operating these reactors in series will allow the required effluent standard of 0.25 mg/L to be met. You are therefore proposing the new configuration for the reactors shown in Figure 1(b)…
The volume of a CFSTR is 45 m' and average constant flow in the reactor is 300 m /d. The reactor flow regime was established by feeding continuously 6 g/L stock tracer solution in the influent line at a rate of 125 L per day. Determine the theoretical tracer concentration in the effluent at 3 and 10 h after the tracer injection. Plot the tracer profile as a function of (a) concentration versus t, and (b) C/Co versus t/0.
1. A CM reactor receives influent containing 10 mg/L of tracer dye for 2 hours. The tracer addition is terminated but the flowrate of water is maintained. The volume of the reactor is 10 L and the flowrate is 2 L/hr. What is the concentration of tracer in the reactor 1 hr after the dye addition is terminated? The reactor had an initial concentration of tracer of 1 mg/L when the tracer addition commenced.
A Pump & Treat water treatment system at a contaminated site is designed to treat 5 m3/d of ground water in a reactor designed as a well mixed system. The effluent must meet quality standards of 25 mg/L of Iron. The treatment reactor’s 20 m3 volume is believed to be insufficient to achieve the standard. The ground water has an iron concentration of 100 mg/L and the treatment reactor has a kinetic constant of 0.5 d-1. – Confirm that the treatment system will NOT meet the effluent quality standards. – If not modify the design by adding a PFR system (using same treatment process and kinetics), what volume should the PFR addition be?
For a completely mixed activated sludge reactor treating municipal wastewater, we can assume the following kinetic and operating parameters: Maximum specific growth rate (μmax) = 3 day-1 Yield = 0.6 mass cells/mass BOD5 utilized Half-velocity coefficient (KS) = 200 mg/L Decay coefficient (KD) = 0.06 day-1 Influent substrate concentration (S0) = 400 mg/L MCRT = 5 days Reactor volume = 3 ML (million liters) Wastewater flow rate (Q) = 10 MLD (million liters per day) Returned activated sludge flow rate (QR) = 5 MLD Calculate the substrate concentration in the effluent (S), cell concentration in the reactor (X), sludge production rate (QWXW), hydraulic retention time (θH), waste sludge flow rate (QW), F/M ratio, and clarifier size.
Environmental Engineering: Water Treatment Please consider each of the following points: a. Determine the required residence time for each reactor of 3 equal volume CSTRs in series given a zero-order reaction with a reaction rate constant, k = -5 mg/L hr. The influent concentration is 125 mg/L and 95% conversion is required across the three-reactor system. What is the total reactor system residence time? b. Determine the required residence time for a single CSTR given the same conditions. c. Determine the required residence time for a PFR given the same conditions. d. Why are all three residence time the same?
4 An activated sludge system is to be used for secondary treatment of 10,000 m³/d of municipal wastewater. After primary clarification, the BOD is 150 mg/L, and it is desired to have not more than 5 mg/L of soluble BOD in the effluent. A completely mixed reactor is to be used, and pilot-plant analysis has established the following kinetic values: Y = 0.5 kg/kg, k, = 0.05 d-¹. Assuming an MLSS concentration of 3000 mg/L and an underflow concentration of 10,000 mg/L from the secondary clarifier (MLVSS=0.8MLSS) determine (1) the volume of the reactor, (2) the mass and volume of solids that must be wasted each day, and (3) the recycle ratio.
A wastewater flow with the following characteristics is to be treated in a completely mixed activated-sludge system. This system is operated at the sludge age of 10d and treats wastewater flowing at 18,000 m3/d. Average influent BOD is 200 mg/L and 92% BOD removal has been achieved. Yield is 0.4 kg biomass/kg BOD and decay coefficient is kd = 0.06 d1. The reactor is designed to operate at a biomass concentration of 2,500 mg/L and the biomass concentration in return sludge is 15,000 mg/L. The mass of solids wasted each day? () tonne/d (*No unit)
1. Draw control volume diagram of reactors for each of the following conditions and write down the mass balance equations using different notations shown in figure: C, Qout Cin Qin V, C Reaction rate constant =k Figure: Sample CMFR/CFSTR showing influent and effluent flows, volume, reaction rate components. a) Steady state CMFR/CFSTR with conservative pollutant b) Steady state CMFR/CFSTR with non-conservative pollutant having first order growth rate c) Non-steady state CMFR/CFSTR with non-conservative pollutants having second order decay rate
Environmental Engineering: Three (3) continuously stirred tank reactors are to be used in series. All the reactors have a similar volume. The influent flow has a concentration 100 mg/L of A and a flow rate of 200 l/min. The reaction is first order and the rate constant is 0.30 hr-1. Using the given information: a. Determine the mean residence time and volume of each reactor if the removal or conversion of A is 90%. b. What are the concentrations of A and the rate of conversion in each reactor?